/usr/lib/ghc-doc/hoogle/data-default-instances-old-locale.txt is in libghc-data-default-instances-old-locale-doc 0.0.1-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-data-default-instances-old-locale-doc/html/data-default-instances-old-locale.txt